The present invention relates to methods for predicting the effects of climate and other environmental conditions on the well-being of animals. Specifically, it relates to a method for accurately calculating the spatial-temporal effects of a variety of environmental conditions on animal individual, population and community dynamics, given the animal's temperature-dependent behaviors, morphology and physiology, by running integrated microclimate and animal models to calculate the discretionary energy and water available to the animal and its activity time.
Animals are affected by the climate and other environmental conditions in which they live. Climate affects animal heat and mass balance and, consequently, body temperature. Spatial and temporal variation in the thermal environment provides a template on which physiological, population and community dynamics are played out. A current challenge in biology is understanding how and when those environmental conditions affect developmental processes and function during the lives of animals. An ability to calculate those effects would enable more accurate prediction and informed decision-making in the management of animal environments. Current trends in global climate shifts, land use and changes to other environmental conditions such as diseases and increases in pesticide use, drive the need for a means to accurately predict their effects to prevent, or at least diminish, their negative impacts on the well-being of animals. The problem is how to model the spatial-temporal effects of climate and other environmental conditions on animals to enable the accurate calculation of those effects.
Explicit calculations of how climate affects animal heat and mass balance, and the consequences for body temperature, were first made in the 1960's (Norris, K. S. 1967. Color adaptation in desert reptiles and its thermal relationships. In: Symposium on lizard ecology, pp. 162–229. U. of Missouri Press, Columbia, Missouri; Bartlett, P. N. and D. M. Gates, 1967. The energy budget of a lizard on a tree trunk. Ecology 48:315–322). Those early models were limited by the lack of models for distributed heat generation internally, distributed evaporative water loss internally, and a first principles model of gut and lung function. Also missing were a first principles model of porous insulation for fur or feathers, an appendage model, and a general microclimate model that could use local macroclimate data to calculate the range of local microenvironments above and below ground.
Since then, several developments have occurred to improve our ability to model the effects of environmental conditions on animals. These include the estimation of convection heat transfer properties from the volume of an animal (Mitchell, J. W. 1976. Heat transfer from spheres and other animal forms. Biophys. J. 16:561–569), a countercurrent heat exchange model for appendages and modifications based on appendage shapes (Mitchell, J. W. and G. E. Myers, 1968. An analytical model of the counter-current heat exchange phenomena. Biophys. J. 8(8):897–911; Wathen, P. et al., 1971. Theoretical and experimental studies of energy exchange from jack rabbit ears and cylindrically shaped appendages. Biophys. J. 11(12):1030–1047; Wathen, P. et al., 1974. Heat transfer from animal appendage shapes-cylinders, arcs, and cones. Trans. of the ASME. November. 40:536–540), the ability to understand the effects of convective heat transport (Kowalski, G. J. and J. W. Mitchell, 1976. Heat transfer from spheres in the naturally turbulent, outdoor environment. J. Heat Transfer 98(4):649–653), the development of a general purpose microclimate model (Beckman, W. A. et al., 1971. Thermal model for prediction of a desert iguana's daily and seasonal behavior. Trans. ASME Paper No. 71-WA/HT-35:1–7; Porter, W. P. et al., 1973. Behavioral implications of mechanistic ecology. Thermal and behavioral modeling of desert ectotherms and their microenvironment. Oecologia 13:1–54; Mitchell, J. W. et al. (eds) 1975. Microclimatic modeling of the desert, pp. 275–286. Scripta Book Co., Washington, D.C.), the ability to calculate the percent of thermally available habitat (Grant, B. W. and W. P. Porter 1992. Modeling global macroclimatic constraints on ectotherm energy budgets. Am. Zool. 32:154–178), the development of porous media models (Kowalski, G. J. 1978. An analytical and experimental investigation of the heat loss through animal fur. In: Department of Mechanical Engineering. University of Wisconsin, Madison, Wis.), the extension of the models to radial instead of Cartesian coordinates and the implementation of first principles fluid mechanics in the porous media (Stewart, W. E. et al., 1993. Prediction of forced ventilation in animal fur under ideal pressure distribution. Functional Ecology 7:487–492; Budaraju, S. et al., 1994. Prediction of forced ventilation in animal fur from a measured pressure distribution. Proc. Roy. Soc. London B 256:41–36; Budaraju, S. et al., 1997. Mixed convective heat and moisture transfer from a horizontal furry cylinder in transverse flow. Int. J. Heat and Mass Transfer 40:2273–2281), and a test of an ecototherm and microclimate model to estimate a species' survivorship, growth and reproduction at a continental scale (Adolph, S. C. and W. P. Porter, 1993. Temperature, activity, and lizard life histories. Am. Nat. 142:273–295; Adolph, S. C. and W. P. Porter, 1996. Growth, seasonality, and lizard life histories. Age and size at maturity. Oikos 77:267–278). However, none of these attempts have accomplished the goal of creating a fully integrated set of models that incorporate all of the conditions needed to accurately predict how animals (both ecototherm and endotherm) will react to changes in their environment.